This invention relates to controlled systems in general and more particularly to improved apparatus for controlling controlled systems with dead time employing a controller with integral characteristic.
Apparatus of this general nature is described in the journal "Technische Mitteilungen AEG-Telefunken" 59 (1969), pages 348 to 352. In the disclosed system a converter control element is influenced exclusively by the output signal of a current controller. Therefore the time behavior of the current controller is a decisive factor in the determination of the time between a change in the reference value and a corresponding change at the output of the controlled system. With this prior art apparatus response times which are about six times the mean statistical dead time of the converter are obtained.
Thus, the need to reduce the response time in apparatus of this type and to make the control behavior of the controlled system independent of the stability limit of the controlled system is evident.